The present invention relates to interactive television systems; more particularly, the present invention relates to an interactive set-top box operating according to a Unified Memory Architecture.
Recently, the popularity of interactive televisions [ITVs] have increased. An ITV is the meeting of television with new interactive technology that takes advantage of current data transferring technology, such as coaxial cable (cable TV cable) or twist copper pair (telephone wire). Typically, ITV is facilitated through an advanced terminal, or set-top box. The set-top box allows users to communicate with an ITV system in order to make perform operations as search the Internet, choose movies, order from catalogs, play games, watch videos, take classes, search through archives, read newspapers, and more.
FIG. 1 is a block diagram of a set-top box 100. Set-top box 100 includes a Central Processing Unit (CPU) 105 and a Motion Picture Experts Group (MPEG) decoder/graphics processor 115. CPU 105 is coupled to a memory 107 and MPEG decoder/graphics processor 115 is coupled to memory 117. Additionally, MPEG decoder/graphics processor 115 is coupled to a display unit. Set-top box 100 may be typically used in applications requiring limited data services. However, in modern ITV systems requiring enhanced data services, set-top box 100 is inadequate.
One problem with set-top box 100 is that memory 117 is not sufficiently large to service both the MPEG decoder and graphics processor applications of MPEG decoder/graphics processor 115. Consequently, the graphics processor operations of MPEG decoder/graphics processor 115 are restricted to four-bit simple graphics, resulting in inadequate color depth. Another problem with set-top box 100 is that the performance interface is not fast enough.
FIG. 2 is a block diagram of a set-top box 200. Set-top box 200 includes a CPU 205, an MPEG decoder 215 and a graphics processor 225. CPU 205 is coupled to a memory 207, while MPEG decoder 215 and graphics processor 225 are coupled to memories 217 and 227, respectively. Graphics processor 225 is also coupled to a display unit. The configuration of set-top 200 solves the deficiencies associated with set-top box 100 by including a separate memory for the operations of graphics processor 225. Nevertheless, adding a separate memory to service graphics processor 225 results in an incremental price increase in the manufacturing of set-top boxes. Therefore, a set-top box that supports enhanced data services without adding a separate memory for graphics functions is desired.
According to one embodiment, an interactive set-top box includes a memory device and a graphics/video processor coupled to the memory device. In addition, the set-top box includes a central processing unit (CPU) coupled to the graphics/video processor and the memory device. Access to the resources of the memory device is shared by the CPU and the graphics processor.